Selecting mechanism of circular knitting machines



July 24, 1956 F. E. DEANS ET AL 2,755,645

SELECTING MECHANISM OF CIRCULAR KNITTING MACHINES 3 Sheets-Sheet 1 FiledOct. 1, 1951 mm v N Am R m: mm o V w w \m 2 um m 9 W mam 3 Q mm Mm Fm WmI 3/, FFI k. 1 F- u I y 4, 1956 F. E. DEANS ET AL 2,755,645

SELECTING MECHANISM OF CIRCULAR KNITTING MACHINES Filed Oct. 1, 1951 3Sheets-Sheet 2 Inventors: D DEA AND FREDERICK 50mm CARLYLE H RBERTuAmwRIG-H July 24, 1956 F. E. DEANS ETAL 2,755,645

SELECTING MECHANISM OF CIRCULAR KNITTING MACHINES ana Inventor-S:FREOERICK sow Q9 1 EANJ AND CARLYLE HERBERT wnmuk 'enf United StatesPatent i SELECTING MECHANISM OF CIRCULAR KNITTHQG MACHINES FrederickEdward Deans and Carlyle Herbert Wainwright, Leicester, England,assignors to The Bentley Engineering Company Limited, Leicester, EnglandApplication October 1, 1951, Serial No. 249,032

Claims priority, application Great Britain October 9, 1950 Claims. CI.66-14) This invention concerns the selecting mechanism of circularknitting machines, primarily circular knitting machines of the opposedneedle cylinder type.

An object of the present invention is an improved selecting mechanismfor knitting machines, and a particular object is a selecting mechanismwhich on the one hand gives a wide range of selection without the use ofa long cylinder or other bed and without it being necessary to cutunduly deep tricks, and which on the other hand permits of the use of apin-drum for controlling the selection. A pin-drum is, for the purposeof this specification, defined as being a drum or cylinder the peripheryof which is provided with circumferential rows of holes (at axiallyspaced levels) for the removable reception of interchangeable pins orscrews in any desired pattern arrangement. Such a device has theadvantage that the pattern arrangement can readily be changed merely byshifting the position (and if necessary altering the number) of thepins.

This invention provides a circular knitting machine, having a trickedinstrument bed, instruments mounted in the tricks for sliding movementsand rocking movements therein and having at contrasting selectinglevels, selecting butts disposed in the required pattern arrangement, anoperating cam for moving along its trick any instrument that it acts on,a depressing cam positioned to engage the instruments and to rock themin their tricks into or out of range of the operating cam, and selectingcams, at the said levels, each movable into and out of operativeposition in which it acts on such selecting butts as may reach it atthat level and thereby slides the associated instrument along its trickto bring it into or out of range of the depressing cam. Preferably, butnot necessarily the instrument is thus moved out of range of thedepressing cam.

It will be seen that the selecting cams only produce part of the slidingmovement of the instruments, this part being that which is required tobring the instruments into or out of range of the depressing cam. Hence,the length of each selecting cam, and the spacing between the variousselecting levels, need only be comparatively small; this in turn permitsof the use of short instruments and of a comparatively short bed whileat the same time permitting a substantial number of selecting cams and aconsequental wide range of selection to be provided. Moreover, thisrange can be achieved without havingthe spacing between the selectinglevels so small as to preclude the use of a pin drum for shifting theselecting cams, it being appreciated that in a pin drum a certainminimum thickness of metal must be left beween pin holes of adjacentcircumferential rows.

It will further be appreciated that since the rocking force is appliedto the instruments from the depressing cam, it can be applied to each ofthem at the same pointin their length, and this point can be widelyspaced from the fulcrum about which they rock; this renders itunnecessary for the tricks to be of inconvenient depth. A

2 ,755,645 Patented July 24, 1956 further advantage of the presentconstruction is than-since the rocking movements are not applied throughthe select= ing butts, the latter can be disposed on both sides of thefulcrum, thereby permitting full use to be made of the length of theinstruments to accommodate rows of selecting butts.

Preferably, the depressing cam operates on the same parts (e. g.operating butts) of the instruments as does the operating cam.

In order to provide for a still greater sliding movement than that whichis derived from the operating cam and the selecting cams, eachinstrument may be provided in its trick with a secondary instrument orbit movable by that instrument, when moved by the operating cam, intorange of an actuating cam which then imparts additional movement to thebit.

It is further preferred to provide axially spaced complimentary guardsextending around the cylinder, one at each side of the fulcrum, for thepositively controlling the angular attitude of each instrument in itstrick through out the entire range of rocking movements.

The foregoing and other features of the invention set out in theappended claims are incorporated in the mechanism that will now bedescribed by way of example with reference to the accompanying drawingsin which:

Figure 1 is a developed view of the interior of the top cam box, lookingon the inside of the cams which control the various instruments in thetop needle cylinder; this figure includes at the right hand side adouble-ended needle, a typical slider, a slidable bit, and a patternjack;

Figure 2 is an elevation of the pin drum and associated parts;

Figure 3 is a side elevation of the mechanism shown in Fig. 2, alsoshowing its attachment to a pillar of the machine frame;

Figure 4 is a plan view taken on the line AA in Fig. 3; V

Figure 5 is a plan view looking on the top of the mechanism shown inFigs. 2 and 3;

Figure 6 is a plan view of one of the cams shown in Fig. 1;

Figure 7 is a sectional view taken on the line 7 7 in Fig. 1.

In this example the invention is to be applied to a super-imposed needlecylinder machine, such as is sold under the registered trademark Komet,for the purpose of controlling the movements of the sliders in the upperneedle cylinder in the production of links-links fabric; Machines ofthis type are well known; they have superimposed coaxial tricked needlecylinders represented diagrammatically at 10 in Figs. 4 and 5 and eachcylinder is equipped with sliders (whereof a representative slider ofthe topcylinder is indicated at 1 in Fig. 1) by which double-endedneedles 75, Fig. 1, are operated. In view of the known character andoperation of such machines, further description or illustration isunnecessary.

In the exercise of the present invention above each sliderinthe topcylinder and in the same trick there is a slidable bit 2 having a butt-3 which throughout the major part of the circle of movement travels ina high inactive track 4 such that the bottom end of the bit is above thehighest position to which thesliders are.

series of selecting levels is provided with a selecting butt.

8. These selecting levels are all of course below the operating butt 7and some of them are below and someabove the fulcrum point 6.

-At a Selecting station which is shown approximately as. the region .Xin Fig. 1 thereis provided a battery of selecting cams, one at eachlevel, these cams are shown as 9 in Fig. 2. Each cam 9 is capable ofbeing moved intowards the cylinder as shown in Figs. 4 and Swhen intowards the cylinder as shown the cam is inthe operative position'andwill engage any selecting butts 8 reaching it at that level. Theoperating butts 7 of the jacks 5 travel throughout the major part oftheir circle of movement in an upper inactive track 11, Fig. 1.Immediately before reaching the selecting station X the operating butts7 are lowered by the levelling cam 12, from the inactive track 11 to thedepressing track 13. If a jack 5 continues in this depressing track itsoperating butt 7 is engaged by the depressing cam 14 (a plan view ofwhich is shown in Fig. 6) which forces or depresses the top end of thejack into its trick and so moves the operating butt 7 that it passesbehind the lowering cam 15 (the operating cam aforesaid) whichimmediately follows the depressing cam 14.

On the other hand if any jack is lowered by a selecting cam 9 Figs. 1and 2 its operating butt 7 is brought down to pass beneath thedepressing cam to a ready track -16 which it travels along intoengagement with the operating cam 15 so that this jack is loweredfurther.

The butts 3 of the bits 2 are also brought down from their inactivetrack 4, immediately before the selecting station X, by thebit-levelling cam 17 which brings them to the selecting track 18 inwhich they are so placed that they will not be further lowered by thejacks 6 at the selecting station X i. e. by the jacks when the latterare lowered by the selecting cams such as 9. However, when a jack 5 islowered by the operating cam 15 it lowers its associated bit 2 from thisselecting track 18 to track 19 in which it passes into engagement withthe bit-actuating cam 20 which lowers that bit still further. Bits thatare not so lowered continue in the selecting track 18 into an idle track18a passing over the top of this actuating cam 20. It will be noticedthat tracks 18 and 18a are intersected by the bolt cam 21 which ineffect constitutes a movable part of the bitactuating cam and may beinserted as required to cause all the bits to be lowered to the readylevel (to be engaged by the actuating cam 20). Bolt cam 21 (as also theother bolt cams herein referred to) is operated in conventional mannerrequiring no description or illustration. The additional movement of thebits 2 by the actuating cam 20 brings them into contact with the sliders(such as 1 in Fig. l) and then moves the latter downwards (e. g. intorange of the transfer control bolt cam 22 and from there onto thetransfer bolt cam 23). Shortly after reaching their lower-most positionthe lowered bits are raised, first to the level of the selecting track18 by means of the cam 24 and then to the inactive track 4 by the returncam 25, thereby serving to lift the associated jacks 5 to their inactivetrack 11 also. Reverting back to the bolt cam 21 it can easily be seenthat by providing the bits 2 with butts 3, Fig. 1, of different length,and by pushing the bolt cam in to differing extents, a selection may beachieved. Specifically, short and medium-length butts may alternate 1 x1 throughout the major part of the circle, except over a short arewherein short and long butts alternate in order to permit of theinsertion of the bolt cam. This permits every second needle to betransferred to the bottom cylinder at the end of an area of fabrichaving a rib-knitted pattern (e. g. a stocking top), so that the firstcourse after the patterned area is knitted of 1 x 1 rib. In thisconnection it will be appreciated that the selecting mechanism providedby the present invention is particularly applicable to the production ofrib-knitted patterns.

If reference is made to Fig. 1 it will be seen that if the pattern jack5 is positioned in its cylinder trick with the butt! running in track 11(as illustrated), the top end 26 is adjacent to the rib 27 (which isshown in side elevation in Fig. 7) of the cam ring, also the bottom end28 of the jack 5 is positioned adjacent the rib 29. Now the two ribs 27and 29-encircle the cylinder and form a guard which positively controlsthe angular attitude of each jack in its trick throughout the entirerange of its rocking movement. The top guard rib 27 is throughout themajor part of the circle rebated at its inner face as shown in Fig. 7 soas to provide a lip 27a which closely encircles the surface of thecylinder and therefore prevents the top ends 26 of the jacks 5 fromswinging outwards and a rebate 27b in which the operating butts 7 of thejacks may move up and down. The levelling cam 12 is in effect a downwardcontinuation of this lip. The depressing cam 14 Fig. 1 is a cam which atits lower part 31 has an incline of its inner face (shown in the planview Fig. 6), in the depressing track 13, in the direction of rotationso as to engage the operating butts 7 in that track to force theminwards, and above said incline has a full thickness part 32 which is,in effect, a continuation of the lip 27a and engages the top ends 26 ofthose jacks which have been lowered by the selecting cams 9 into theready track 16, and prevents these top ends from swinging outwards. Theoperating cam 15 (or lowering cam) is also of full thickness except atits reverse edge 36 where its inner face is formed with a reverseincline hereinafter described. Beyond the operating cam .15, the guardrib continues at full thickness (indicated by the earns 33 and 34)until, approximately at a stage where the bits are lifted to the idletrack 11 by their return cams 24 and 25, it re-assumes the aforesaidlipped rebated formation. It does so in cam face 35 which serves tolower the jacks 5 to the depressing level 13 during reciprocation in theheel and toe (the selecting cams 9 then being out of operation) whereattheir operating butts 7 are engaged and depressed by the reverse incline36 on the operating cam 15.

It is now convenient to refer to the bottom guard rib 29. Throughout themajor part of the circle this guard rib is a plain rib which closelyencircles the surface of the cylinder and so prevents the bottom ends 28of the jacks 5 from rocking outwards, without preventing their slidingmovements. Immediately before the selecting station X this rib mergesinto the bit levelling cam 17. Immediately below the depressing cam 14the bit levelling cam 17 is provided with an incline 37 which iscomplementary to (i. e. is sloped in the opposite direction to) that ofthe depressing cam incline 31, so as to permit the lower ends 28 ofthose jacks, which are depressed by the depressing cam 14, to swingoutwards. Below this reverse incline 37, the bit levelling cam 17 has alip 17a of full thickness which holds in the lower ends 28 of thosejacks which have been lowered by a selecting cam 9 and thus have notbeen engaged and rocked by the depressing cam 14. Continuing from thisreverse incline 37 above the top of the bolt cam 21 and half way alongthe top of the actuating cam 20, there is a guard cam 38 which is of Lsection, having a rebate 38a to accommodate the protruding lower ends 28of those jacks which have been rocked by the depressing cam 14 and abottom lip 39 which holds into their tricks the bottom ends 28 of thosejacks which have been lowered by the lowering cam 15. At the regionsubstantially above the apex of the bitactuating cam 20 and belowincline 36 this rebate merges byan incline 40 into a full thicknessguard cam.

During rotational knitting, this incline 40 serves to press the lowerends 28 of all jacks into their tricks and during the heel and toe itpermits said lower ends to move out before the upper ends 26 of thejacks are pressed in by the reverse incline 36 on the operating cam 15.

It will be appreciated that the jacks have three stages of downwardsmovement, (a) from .the inoperative track 11 to the depressing track 13by the levelling cam 12, (b) from the depressing track 13 to the readytrack 16 by the selecting cams 9, (c) from the ready track 16,

by the operating cam 15. The bits likewise have three stages of movement(a) from the inactive track 4 to their selecting track 18, by thebif-levelling cam 17, (b) from their selecting track 18 to the readytrack 19 by the jacks 5 being lowered by the operating cam and (c) to afourth and lowest level 41, by the actuating cam 20. As a result thetotal movement imparted by the bits 2 to the sliders l is much greaterthan can be derived directly from the selecting cams 9. Moreover, sincethe sliding movement required to be imparted to a jack 5 to cause itsoperating butt 7 to miss its depressing cam 31 is very small theselecting butts 8 and the selecting cams 9 may be closely spaced whichin turn permits of a great number of selecting levels and of a wideselecting scope without an undue length of cylinder. On the other handthe pitch between the selecting levels may well be sufliciently large topermit the use of a pin-drum for operating the selecting cams.

Each selecting cam conveniently consists of a strip of sheet metal suchas 9 Figs. 2, 4 and 5, disposed radially of the cylinder 10 at station Xbut with its under face at the angle required to engage and lower theselecting butts 8. These strips 9 are guided as shown in the verticalpost 42 of U section which is supported at the correct height andposition by the flat plate 43 which is itself fixed to the pillar 4-4.The pillar 44 is therefore used not only as a spacer between the topcasting 45 and the bottom plate 46 of the pin-drum assembly but also maybe rotated to give the correct position for the guide post 42 and thenlocked in position.

As can be seen in Fig. 4 each of the selector cams (or blades 9) has twobutts 47 and 48 between which the end of a selector lever such as 49 isinserted. These selecting levers 49 are fulcrummed intermediate theirends at 50 and have one end guided in the vertical comb 68 and at theirother end 51 they are also guided in a comb 52 (Figs. 3 and 4) which isanother spacing pillar for the top casting 45 and bottom plate 46. Thelevers 49 are of sheet metal and are quite flat It is usual to pivotsuch a battery of levers on a spindle which transfixes them all. In thepresent instance each transmitting lever 49 has a fulcrum notch at 50 inwhich is engaged the rounded vertical edge of a fulcrum plate 53. Thelevers 49 are each provided with a tension spring 54 extending betweenit and the abutment 55 on the plate 53, for holding its fulcrum notchagainst the fulcrum edge. These springs also serve to urge the ends ofthe levers towards the pin-drum 55.

If reference is made to Fig. 4 it will be seen that the fulcrum plate 53is joined securely to the block 67 which is pivoted on the spindle 56;the block 67 carries a stop screw 69 which butts up to the pillar 70. Itcan now be seen that if the block 67 is turned on the spindle 56 in ananti-clockwise direction it will swing the fulcrum plate 53 which willitself move the levers 49 in towards the pin-drum 55. Now the ends 51 ofthe levers 49 which are guided in the slots in the pillar 52, will pivoton the back of the slots as the fulcrum plate 53 is moved and cause theother ends of the levers 49 to slide in the comb 6S and move the blades9 away from the cylinder 10, thus putting the whole bank of selectorblades 9 out of action. From the foregoing description it can easily beseen that to place the bank of blades 9 into action the block 67 must beturned on the spindle 56 in a clockwise direction. In Fig. 4 the block67 is turned on its spindle 56 by means of the lever 57 and is thereshown in the position where the end 65 of the lever is clear of theabutment 66 of the fulcrum plate 53 thus allowing the selector levers 49to pivot on their ends 51 under the action of the springs 54 which hascaused two things to happen, namely, the blades 9 have been projected intowards the cylinder 10, and the fulcrum plate 53, together with theblock 67, has turned on the spindle 56 to the extent allowed by thestop-screw 69 butting up to the pillar 70. This stop-screw is set toallow the blades 9 to be projected until they are just clear of thecylinder 16-.

It may be desirable to devote the top part of the drum '55 to onepattern (e. g. for the turnover top of a stocking) and the lower part toanother pattern (e. g. for the leg of a stocking) and to render eitherpart of the drum inoperative while the other part is in use; For thispurpose the fulcrum plate 53 may be made in upper and lower parts 53a,53b (shown in Fig. '2 Where the plate 53 is split 'or divided along theline corresponding to the respective parts of the drum, either of which(together with the group of levers 49 pivoted on it) may be swung to theoperative or inoperative position as above described. Both parts may beswung at the same time to render the Whole of the drum operative orinoperative.

The controls to both parts 53a, 53b of the fulcrum plate are shown inFigs. 2 and 3, the levers 57 and 58 con trolling the top and bottomplates respectively. These two levers are shown mounted freely on theshaft 59 and positioned at the correct height by the collars 60 andspring 61-, they are constantly urged in one direction by the springs63, 64, and actuated when required by the cables 71, 72, the other endsof which are attached suitably to lifter rods operating directly fromthe main controldrum of the machine (or are otherwise operated inconventional manner). It is by operation of the levers 5'7, 58 by meansof the cables 71, 72 thatthe selecting cams 9 as a whole are moved outof operation for the period during which reciprocatory knitting occursfor the purpose of heel and toe formation.

The pin-drum 55 may be of any known construction but is preferablyconstructed according to co-pending patent application No. 249,232 filedOctober 2, 1951 (to which reference isto be made for furtherparticulars) and is capable of being racked in either direction. Thetransmitting levers 49 may also be arranged as described in thatapplication. As far as the mechanism here described is concerned sufficeit to say, that, when a pin such as 73, Fig. 4 is racked between theprojection 74 of the lever 49 and the surface of the pin-drum it willcause the lever to fulcrum on the corner 50 of the plate 53, and thusthe end located between the butts 47 and 48 of the selector blade 9 willretract the said blade to its inoperative position and so allow the butt8 of the jack Fig. l to pass by.

We claim:

1. A circular knitting machine having a tricked instrument bed,instruments mounted in the tricks for sliding movements and rockingmovements therein about an intermediate fulcrum and having atcontrasting selecting levels on both sides of the fulcrum, selectingbutts disposed in the required pattern arrangement, an operating cam formoving along its trick any instrument that it acts on, a depressing campositioned to engage the instruments and to rock them in their tricks tocontrol their engagement with the operating cam, and selecting cams, atthe said levels, each movable into and out of operative position inwhich it acts on such selecting butts as may reach it at that level andthereby slides the associated instrument along its trick to control itsengagement with the depressing cam.

2. A machine according to claim 1, wherein the said associatedinstrument is movable by the selecting carns out of range of thedepressing cam.

3. A machine according to claim 1, incorporating a pind'rum forselecting the selecting cams.

4. A machine according to claim 1, having the instruments formed with afulcrum substantially midway between their ends.

5. A machine according to claim 1, having the depressing cam arranged tooperate on the same parts (e. g. the operating butts) of the instrumentsas does the operating cam.

6 A machine as claimed in claim 1 having axially spaced complementaryguards extending round the cylinder, one at each side of the fulcrum,for positively controlling the angular attitude of each instrument inits trick throughout the. entire range of rocking movements.

7., A circular knitting machine having a tricked instrument bed,instruments mounted in the tricks for sliding movements and rockingmovements therein about an intermediate fulcrum and having atcontrasting selecting levels on .both sides of the fulcrum selectingbutts disposed in the required pattern arrangement, an operating cam formoving along its trick any instrument that it acts on, a depressing campositioned to engage the instruments and to rock them in their tricks tocontrol their engagement with the operating cam, selecting cams at thesaid levels each movable into and out of operative position in which itacts on such selecting butts as may reach it at that level and therebyslides the associated instrument along its trick to control itsengagement with the depressing cam, and the machine being arranged toknit by reciprocation as well as by rotation, and having an incline fordepressing the instruments out of range of the operating cam in eachreverse swing of reciprocatory knitting.

8. A machine as claimed in claim 7 having means for rendering theselecting cams inoperative during reciprocatory knitting.

9. A circular knitting machine having a tricked instrument bed,instruments mounted in the tricks for sliding movements and rockingmovements therein about an intermediate fulcrum and having atcontrasting selecting levels on both sides of the fulcrum selectingbutts disposed in the required pattern arrangement, an operating cam formoving along its trick any instrument that it acts on, a depressing campositioned to engage the instruments and to rock them in their tricks tocontrol their engagement with the operating cam, selecting cams atthesaid levels each movable into and out of operative position in whichit acts on such selecting butts as may reach it at that level andthereby slides the associated instrument along its trick to control itsengagement with the depressing cam, and having each instrument providedin its trick with a secondary'instrument or bit movable by thatinstrument, when moved by the operating cam, into range of an actuatingcam which then imparts additional movement to the bit.

10. A machine as claimed in claim 9 having a third instrument movable byeach bit and actuating cams into range of which the third instrument isthereby brought,

11. A machine as claimed in claim 10 being of the opposed needlecylinder type, wherein the third instruments are needle-controllingsliders and the actuating cams therefore are transfer cams fortransferring needles from cylinder to cylinder.

12. A circular knitting machine having a tricked instrument bed,instruments mounted in the tricks for sliding movements and rockingmovements therein about an intermediate fulcrum and having atcontrasting selecting levels on both sides of the fulcrum selectingbutts disposed in the required pattern arrangement, an operating cam formoving along its trick any instrument that it acts on, a depressing campositioned to engage the instruments and to rock them in their tricks tocontrol their engagement with the operating cam, selecting cams, at thesaid levels, each movable into and out of operative position in which itacts on such selecting butts as may reach it at that level and therebyslides the associated instruments along its trick to control itsengagement with the depressing cam, a secondary instrument or bitprovided for each instrument in its trick and movable by thatinstrument, when moved by the operating cam, into range of an actuatingcam which then imparts additional movement to the bit, and wherein theinstruments and the bits have threestages of movement, the stages fortheinstruments being from an inoperaive track to a de pressing track bymeans of a levelling cam in which depressing track the instruments aredisposed to be acted on by the depressing cam, from the depressing trackto a ready track by the selecting cams in which ready track theinstruments are disposed to be'acted on by their operating cam, and fromthe ready track by the depressing cam, and the stages for the bits beingfrom an inactive track to a selecting track by a bit-levelling cam, fromthe selecting track to a ready track by movement of the instruments bytheir operating cam, in which selecting track the bits are disposed tobe acted on by the bit-actuating cam, and to a further level by thebit-actuating cam.

13. A machine as claimed in claim 12 wherein the selecting track for thebits is intersected by a movable part of the bit-actuating cam, saidmovable part being movable to an inoperative position.

14. A machine as claimed in claim l2 having return cam means acting onthe bits after the bit-actuating cam to lift the bits to the inactivetrack and the instruments to their inoperative track.

15. A circular knitting machine having a tricked instrument bed,instruments mounted in the tricks for sliding movements and rockingmovements therein about an intermediate fulcrum and having atcontrasting selecting levels on both sides of the fulcrum selectingbutts disposed in the required pattern arrangement, an operating cam formoving along its trick any instrument that it acts on, a depressing campositioned to engage the instruments and to rock them in their tricks tocontrol their engagement with the operating cam, selecting cams at thesaid levels each movable into and out of the operative position in whichit acts on such selecting butts as may reach it at that level andthereby slides the associated instrument along its trick to control itsengagement with the depressing cam, a secondary instrument or hitprovided for each instrument in its trick and-movable by thatinstrument, when moved by the operating cam, into range of an actuatingcam which then imparts additional movementto the bit, and wherein theinstruments and the bits have three stages of movement, the stages forthe instruments being from an inoperative track to a depressing track bymeans of a levelling cam in which depressing track the instruments aredisposed to be acted on by the depressing cam, from the depressing trackto a ready track by the selecting cams in which ready track theinstruments are disposed to be acted on by their operating cam, and fromthe ready track by the depressing cam, and the stages for the bits beingfrom an inactive track to a selecting track by a bit-levelling cam, fromthe the selecting track to a ready track by movement of the instrumentsby their operating cam, in which selecting track the bits are disposedto be acted on by the bitactuating cam, and to a further level by thebit-actuating cam, and wherein the selecting track for the bits isintersected by a movable part of the bit-actuating cam, said movablepart being movable to an inoperative position, and having return 'cammeans acting on the bits after the bit-actuating cam to lift the bits tothe inactive track and the instruments to their inoperative track.

References Cited in the file of this patent UNITED STATES PATENTS892,162 France Ian, 3, 1944

